1. Field of the Invention
The present invention relates to a central air-conditioning system that conditions a plurality of rooms in a house with a single air-conditioning unit.
2. Description of the Related Art
A central air-conditioning system is known that conditions a plurality of rooms in a house using a single air-conditioning unit, such as a heat pump. In the central air-conditioning system, the air-conditioning unit and each room are connected by air-conditioner ducts. Cold air or warm air generated by heat exchange performed in the air-conditioning unit is supplied to each room via the air-conditioner ducts. A controller of the central air-conditioning system individually controls the temperature of each room to a desired set temperature using the cold air or warm air sent from the air-conditioning unit.
Measures supporting the energy-conservation consciousness of recent years are essential also in a central air-conditioning system such as this. Therefore, an energy conservation measure is proposed for central air-conditioning systems in which a controller controls the temperature of a room in which a person is present, among a plurality of rooms in the house, to a comfort temperature near a set temperature and controls the temperatures of the rooms in which the person is not present to an energy-saving temperature that differs by several degrees Celsius from the set temperature, as shown in Japanese Patent Laid-open Publication No. 11(1999)-294839.
However, when temperature control is switched under a condition that the person is present in the room or is not present in the room as in Patent Literature 1, it is difficult to quickly change the temperature of a room the person has entered, when the person enters an unoccupied room. In other words, the central air-conditioning system simultaneously conditions the plurality of rooms within the house. Therefore, in the central air-conditioning system, it is difficult to quickly make comfortable the temperature of a room a person has newly entered while maintaining a comfortable temperature in a room in which a person is already present.
In addition, in the central air-conditioning system, temperatures of the plurality of rooms in the house are controlled to an ordinary set temperature or an energy-saving temperature closer to the outside temperature than the ordinary set temperature, following a schedule set in advance. In this instance, the temperatures of the plurality of rooms in the house are controlled in adherence to the schedule regardless of whether people are present in the rooms. For example, the temperature of a room that is scheduled to be controlled to the ordinary set temperature is maintained at the ordinary set temperature regardless of whether a person is present in the room. Therefore, energy is wasted, going against the demand for energy-saving measures. On the other hand, when a room originally intended to be controlled to the ordinary set temperature is controlled to the energy-saving temperature near the outside temperature when a person is not present, the temperature of the room is not maintained at the ordinary set temperature when a person enters the room. A problem occurs in that comfort is sacrificed.